three at the back - help?

Hi all, attempting new things after being an advocate of a control based 4-3-3 (with three true strikers) for quite some time. I'm fancying a 352 or 3511 for more tactical flexibility. Are there any general rules to a back three I should be considering?

I've tried the common sense approach to defensive wingers and an anchor man to protect the back three, but I'm still finding it difficult to defend against width and build possession.

At the moment I had a cover defender lcb, stoppr cb and a ball playing rcb.

Usually I'm a fan of the TaP partnership upfront, but I'm also finding in this tactic it simply isn't working.

Any help is appreciated guys!

I've just embarke on something similar with my Eastleigh side in league 1. As yet we haven't conceded in pre-season (take from that what you will) against St Pats, Shelbourne, Cork and Aston Villa. My side is based on wing backs so really you could call it either a 352 or a 532. In reality and complex terms it's more a: 3-2-1-2-2

3 Solid centre halves
2 wing backs
1 central midfielder
2 attacking midfielders (AML/AMR)
2 centre forwards (applying TaP at the moment)

I base all of my sides around possession so my self-inflicted rules are around short passing and hassling opponents. Something I'd certainly suggest is a high work rate for both of your wing backs and the central player as you'd expect they'll do a lot of running!